Google 测试工作操作的返回垃圾值

Question

我已经在我的主文件中手动测试了 .decreaseInventory()，所以我知道它可以正常工作，但是当我运行对它进行 google 测试时，它失败并给我一个错误。我该如何解决这个问题？

玩家class:

#ifndef PLAYER_H
#define PLAYER_H

#include <iostream>  
using namespace std;

class Player
{

    int inventory;

public:
    Player();
    int decreaseInventory(int numOfBeers);
    void setInventory(int newInventory);
    int getBackOrder();
    int getCost();
    int getInventory();

    bool operator ==(Player& p);
};

Player::Player()
{
    cout << " Default Player Constructor\n";
    inventory = 12;
    backorder = 0;
    cost = 0;
    orderDelay = 0;
    shipmentDeplay = 0;
}

void Player::setInventory(int newInventory)
{
    inventory = newInventory;
}

int Player::decreaseInventory(int numOfBeers)
{
    inventory = inventory - numOfBeers;
}

int Player::getInventory()
{
    return inventory;
}

test.cpp:

#include "gtest/gtest.h"
#include "Player.h"

TEST(playerTest, decreaseInventoryTest ) {

    Player p;
    int curr_inv = p.getInventory();
    EXPECT_EQ(curr_inv-3, p.decreaseInventory(3));

}

错误：

Running main() from gtest_main.cc
[==========] Running 1 test from 1 test case.
[----------] Global test environment set-up.
[----------] 1 test from playerTest
[ RUN      ] playerTest.decreaseInventoryTest
 Default Player Constructor
/home/hammad/se-02-team-21/tests.cpp:13: Failure
      Expected: curr_inv-3
      Which is: 9
To be equal to: p.decreaseInventory(3)
      Which is: 1740894128
[  FAILED  ] playerTest.decreaseInventoryTest (1 ms)
[----------] 1 test from playerTest (1 ms total)

[----------] Global test environment tear-down
[==========] 1 test from 1 test case ran. (1 ms total)
[  PASSED  ] 0 tests.
[  FAILED  ] 1 test, listed below:
[  FAILED  ] playerTest.decreaseInventoryTest

 1 FAILED TEST

为什么会失败并给出垃圾值？我已经在使用默认构造函数，并且通常它可以正常工作。

Answer 1

您的 decreaseInventory 函数定义中缺少 return 值。要解决此问题，只需 return inventory 成员变量的（修改后的）值：

int Player::decreaseInventory(int numOfBeers)
{
    inventory = inventory - numOfBeers;
    return inventory; // You need to return the modified value!
}

Answer 2

你的方法是：

int Player::decreaseInventory(int numOfBeers)
{
    inventory = inventory - numOfBeers;
}

您的测试是：

EXPECT_EQ(curr_inv-3, p.decreaseInventory(3));

宏 EXPECT_EQ 比较从 p.decreaseInventory(3) 编辑的值 return 与 curr_inv-3。该方法没有 return 任何东西。

不从声明为 return 的方法中 returning 某些东西是未定义的行为。你的编译器应该已经警告过你，你的测试是成功的，因为你有一个失败的测试是由你现在可以修复的代码中的一个真正的错误引起的。

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